Hydraulic starter



p 2, 1952 A. c. JENNY HYDRAULIC STARTER 2 SHEETS-SHEET 1 Filed May 241951 ATTORNEY Sept. 2, 1952 A. c. JENNY 2,608,966

' HYDRAULIC STARTER Filed May.24, 1951 2 SHEETSSHEET 2 N i A, O N RI; 2/"2| g,

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ALBERT c. JENNY MAW ATTORNEY Patented Sept. 2, 1952 UNITED STATES PATENT0F HYDRAULIC STARTER Albert C. Jenny, ClevelandLl'Ohio, assignor to Jack& Heintz Precision Industries, Inc, Cleveland, Ohio, a corporation ofDelaware 7 Application May24, 1951 Serial No. 228,605,

This invention relates in general to hydraulic starters for engines andmore particularly to that type of starter employing a rotating cylinder.

In starter drives of the hydraulic type','it is conventional practice toso construct and arrange the hydraulic motor, drive and porting plate asto provide for the extension of the starter pinion into full mesh withthe engine flywheel ring gear prior to any rotation of the drive shaftand to then suddenly initiate a full speed rotation of the motor anddrive thereby of the drive shaft.

It is particularly true in hydraulic motor starters that a straightlinear extension of the starter pinion, with no rotation thereof, willnot insure proper mesh of the pinion with the ring gear, inasmuch asthere is always the possibility of head-on engagement of the teethwithout proper mesh. This not only means lack of engagement but alsopresents the danger ofteeth .chattering and destruction when full speedrotation of the motor and drive shaft are applied without previous fullpinion and ring gear" mesh. Accordingly, one of the primary objects ofmy invention is to provide in such a device a meter ing means for thehydraulic system whereby as the starter pinion is being extended, themotor operated drive shaft will be slowly rotated until the starterpinion and engine flywheel ring gear are fully meshed, after which timeafull flow of hydraulic fluid is fed to the motor to obtain full speedrotation of the motor and its drive shaft.

Another object is to provide in such a hydraulic pressure system,involving a pinion and piston normally spring retracted, a fluid controlto cushion the forward travel of the pinion extending piston and a fluidcontrol to force the piston forward and simultaneously cause slowrotation of the motor and'drive shaft to obtain full mesh with theengine ring gear before full rotation of the motor, drive shaft and themeshing gears.

Another object is to provide in the hydraulic system a fluid meteringsystem that will, upon operation of a suitable manual control, not onlyinsure linear extension of the starter pinion by the piston andsimultaneous slow rotation of the pinion by the motor until full meshwith the engine ring gear and thencause full speed rotation. of, themotor andstarter pinion, but will also prevent reengagement'of thestarter pinion with. the engine flywheel ring gear, after the startingof the engine has kicked the starter pinionqout of mesh, even though theoperator 3 Claims. (01. izaqnn 2 inadvertently continues to apply themanual control which initiated the engine starting operation. l

'With'the foregoing and other objects in View, the invention residesin'the combination of parts and in the details of constructionhereinafter set forth in the following specification and appendedclaims, certain embodiments thereof being illus-s trated in theaccompanying drawings, in which: Figure 1 is a view in longitudinalsection taken through the hydraulic starter assembly, showing the samein retracted position; Figure 2 is a viewin end elevation of the porting plate; l

Figure 3 is an enlarged detail sectional view taken along line-3 ofFigure 2,"through the engaging head casing; s a

- Figure 4 is an enlarged detail sectional view taken along line 4-4 ofFigure 2g-and Figure 5 is a'view similar to Figure 1, showing thestarter assembly in extended position.

Referring more particularly to the drawings; the hydraulic starter isshown to-includean engaging head casing I, a porting plate 2 and ahydraulic motor casing 3. Suitable securing means may be employed tofasten the casings and porting plate together.

Positioned axially within the starter is a rotatable shaft 4 which iscarried at one end in a bearing 5 of casing I and at the other end by abearing 6 of casing 3. A wobble plate 1- is carried between shoulders 8and 9 by means oia ball bearing assembly H1. The wobble-plate l is pressfitted into the inner race It and the draulic fluid from a suitablesource, such asan; accumulator, the fluid flow being under conventionalmanual control. Inlet l6 communicates with an arcuate inlet'port I! inthe porting-plate 2. An exhaust port H3 in casing l communicates with anarcuate outlet port IS in porting plate 2.

Slidably, mounted in casing l is a piston 20 with a reduced hollow stem2| .to leave a chamber 22 in the casing about the piston stem.Surrounding stem 2| is a compression coil spring.

23 that bears against casing shoulder 24- and the piston 20 to normallyforce the piston fully to the right into the retracted position ofFigure 1.

Shaft 4 is provided with helical threads 25 to be engaged by the starterpinion 26 which is normally held in the retracted position of Figure 1by a compression coil spring 2! bearing against a shaft collar 28 andagainst the pinion to urge the latter to the right against a plate 29and the latter against the front, or left, end of the piston stem 2 I.

In the at rest retracted position of Figure 1 with the hydraulic motorstationary, the reduced passage l6, from the hydraulic inlet [6,slightly overlaps in communicating relationship with a radial port 3| inpiston 2|] that communicates with a longitudinal passage 32 leading tochamber 22 and through a restricted longitudinal passage 33 into chamber30 behind the piston.

When the conventional starter control valve is manually opened, thehydraulic fluid is released from its accumulator to flow under pressurethrough the inlet I6, and inlet port It, and through passages 32 and 33into chambers 22 and 30. The larger passage 32 lets fluid into chamber22, in which spring 23 is located, to provide a dashpot for the forwardmovement of the sleeve piston 20. The relatively smaller passage 33meters the fluid flow at a reduced rate into chamber 30 on the back faceof the large diameter of the sleeve piston head. This fluid pressureforces the piston, and consequently the starter pinion 26, linearlyforwardly to the left into meshing engagement with the engine flywheelring gear 45, as shown in Figure 5. This operating of the sleeve pistonis afiected by the differences in the pressure areas between the sleeveand shaft diameters, which makes the sleeve a differential piston. Thesleeve also operates against two springs 23 and 21 which reduces therate at which the sleeve is extended and aids in retracting the pinionafter the engine cranking cycle is completed.

Leading to the inlet port H is an inlet passage 34 that is normallyclosed from passage It by the piston head. Leading from chamber 22 topassage 34 is a restricted passage 35 in the piston head. Also locatedin a bore in the piston head is a poppet valve 36, spring urged to theright to open by a compression coil spring 31 and leading from the borein which the poppet valve is located is a passage 38 leading to inletpassage 34 to the hydraulic motor. The function of the poppet valve inthe hydromesh sleeve piston is to allow fluid trapped at the large headend of the piston to escape to the motor and to let the sleeve returnquickly so as to allow the starter pinion to get out of mesh quicklyafter the engine has been started. a a

With less than 125 pounds per square inch in the pressure passages, thepinion and sleeve spring push the sleeve all the way back into theretracted position of Figure l, forcing the' poppet valve against theporting plate 2, holding it closed against its seat against the actionof spring 31. This is the condition before the cranking cycle.

, When fluid pressure is admitted sufficient to start pushing the sleeveoutwardly to the left, this fluid, pressure holds the poppet valveclosed against its seat and the poppet valve remains closed until thesleeve pushes out and uncovers the main passages. At this point thepressure on both sides of the poppet valve becomes equal and spring 3!acts to open the poppet valve. The poppet valve will remain open untilthe main .manual control valve is closed, at which time the springpressure on the sleeve will seat the poppet valve upon its abutment withthe porting plate. In other words, if the operator opens the controlvalve to start the engine and holds the valve open after the enginestarts the starter pinion will withdraw from the engine flywheel ringgear and continue to revolve slowly in a neutral unmeshed position. This'is' accomplished by spacing the poppet valve port with respect to themotor intake port 34 so that it will cut oil? the main fluid flow atapproximately one sixteenth of an inch from the point of closing of thepoppet valve and continue to bleed off the pressure fluid through to themotor without changing the hydromesh sleeve position. Any

discontinuance in fluid pressure from the main manual control will allowthe sleeve to drift back and reset the poppet valve for another enginecranking operation of the assembly.

As an added precautionary refinement, I provide in the main casing l alongitudinal bore 39 communicating through a radial passage 40 withchamber 22. In 'bore 39 I insert a screw plug 4| having a passage 42therein and a seat to accommodate a ball 43 normally urged against theseat by a compression coil spring 44 to keep passage 42 normally closed.This is to insure against the building up of excessive fluid pres.-sures on the right side of the piston head. If such undesired fluidpressures exist the ball 43 will be unseated against the action ofspring 44 and fluid will flow from chamber 30 through passages .42, 39and 40 into chamber 22. Such a condition might arise in the event thepoppet valve 36 should stick in its closed position after the engine hasfired.

I claim:

1. An hydraulic starter for engines comprising a housing, a rotatabledrive shaft, a sleeve splined thereto for sliding movement thereon andfor rotatable drive thereby, said sleeve having a piston head at its oneend and a starter pinion at its other end for engaging an engine gear,an hydraulic motor for driving said shaft, a porting plate, a fluidinlet and outlet-port for said housing, said motor having an inlet andoutlet port, said motor having an inlet port, means for impartinghydraulic driving power to said sleeve to extend it and said pinion to apredetermined extent While simultaneously imparting hydraulic drivingpower to said motor to rotate said shaft relatively slowly and uponfurther extension of said pinion into mesh with the gear to be driventhereby to rotate said shaft and pinion at a relatively greater speed,said means comprising spring means for normally retracting said starterpinion, an annular chamber surrounding said sleeve, a spring in saidchamber for normally retracting said pinion and maintaining a restrictedcommunication between said inlet port and said annular chamber, arestricted chamber on the opposite side of said piston from said springand a restricted communication between said annular chamber and saidrestricted chamber, for metering the fluid flow from the inlet port tothe restricted chamber until said piston is forced past said inlet, atwhich time full fluid flow is obtainedfrom said inlet motor.

2. An hydraulic starter for engines comprising a housing, a rotatabledrive shaft, a sleeve splined' ton head at its one end and a starterpinion at its other end for engaging an engine gear, an hydrau lic motorfor driving said shaft, a porting plate, a

fluid inlet and outlet" port for said housing, said motor having aninlet and outlet port, said motor having an inlet port, means forimparting hydraulic driving power to said sleeve to extend it and saidpinion to a predetermined extent while simultaneously impartinghydraulic driving power to said motor to rotate said shaft relativelyslowly and upon further extension of said pinion into mesh with the gearto be driven thereby to rotate said shaft and pinion at a relativelygreater speed. said means comprising spring means for normallyretracting said starter pinion, an annular chamber surrounding saidsleeve, a spring in said chamber for normally retracting said pinion andmaintaining a restricted communication between said inlet port and saidannular chamber, a restricted chamber on the opposite side of saidpiston from said spring and a restricted communication between saidannular chamber and said restricted chamber, for metering the fluid flowfrom the inlet port to the restricted chamber until said piston isforced past said inlet, at which time full fluid flow is obtained fromsaid inlet to said motor, a second passage between said annular chamberand the opposite side of said piston and a poppet valve in said passage,a spring to urge said poppet valve open,said poppetvalve being heldclosed by abutment with said porting plate under urging of said sleevespring and also under high fluid pressure on said piston head in theextension stroke of the starter pinion for the purpose of allowing fluidtrapped in said annular passage to escape to said motor to permit saidsleeve to return quickly to retracted position under the urging of saidsleeve spring to retract and maintain said starter pinion out of meshwith said engine gear after said engine has been started.

3. An hydraulic starter for engines comprising a housing, a rotatabledrive shaft, a sleeve splined thereto for sliding movement thereon andfor rotatable drive thereby, said sleeve having a piston head at its oneend and a starter pinion at its other end for engaging an engine gear,an hydraulic motor for driving said shaft, a porting plate, a fluidinlet and outlet port for said housing, said motor having an inlet andoutlet port. said motor having an inlet port, means for impartinghydraulic driving power to said sleeve to extend it and said pinion to apredetermined extent while simultaneously imparting hydraulic drivingpower to said motor to rotate said shaft relatively slowly and uponfurther extension of said pinion into mesh with the gear to be driventhereby to rotate said shaft and pinion at a relatively greater speed,said means comprising spring means for normally retracting said starterpinion, an annular chamber surrounding said sleeve, a spring in saidchamber for normally retracting said pinion and maintaining a restrictedcommunication between said inlet port and said annular chamber, arestricted chamber on the opposite side of said piston from said springand a restricted communication between said annular chamber and saidrestricted chamber, for metering the fluid flow from the inlet port tothe restricted chamber until said piston is forced past said inlet, atwhich time full fluid flow is obtained from said inlet to said motor, asecond passage between said annular chamber and the opposite side ofsaid piston and a poppet valve in said passage, a spring to urge saidpoppet valve open, said poppet valve being held closed by abutment withsaid porting plate under urging of said sleeve spring and also underhigh fluid pressure on said piston head in the extension stroke of thestarter pinion for the purpose of allowing fluid trapped in said annularpassage to escape to said motor to permit said sleeve to return quicklyto retracted position under the urging of said sleeve spring to retractand maintain said starter pinion out of mesh with said engine gear aftersaid engine has been started, a third passage between said annularchamber and the opposite side of said piston and a check valve in saidpassage, a spring to urge said check valve away from said annularchamber to closed position and adapted to be opened against the actionof its spring upon building up of excess pressure on said piston head inthe event of mulfunctioning of said poppet valve in closed position toinsure escape of fluid trapped in said annular chamber to said motor.

ALBERT C. JENNY.

REFERENCES CITED UNITED STATES PATENTS Name Date Molyneux et al. Feb.28, 1950 Number

